Blowing device



Aug. 10, 1943. w. A. MORRISON BLOWING DEVICE Filed July 23, 1942 \NVENTOR H ZZHawA-Morvisom H S ATTORN EY.

7 piston chamber 25 Patented Aug. 10, 1943 BLOWING DEVICE William A. Morrison, Easton, Pa., assignor to Ingersoll-Rand Company, New York, N. Y. a

corporation of New Jersey v V Applio'ation July 23, 1942, Serial Nb. 452,068 g V 4 Claims. (01. 121-10) 1 This invention relates to rock drills, and more particularly to a blowing device for fluid actuated rock drills of the hammer type,

One object of the invention is to assure an uninterrupted flow of pressure fluid under-full line pressure into a rock cuttings whenever thevmeans ordinarily performing the cleansing function proveinadequate for maintaining a clean working surface Other objects ,will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts, a

Figure 1 is an elevation, partly in section, of a rock drill equippedvwith a blowing device constructed in accordance with th 'practice of the ments of the rock drill rock drill, and I t Figure 2 is a similar view'showing the ;valve and piston elements inthe positions which they .will occupy when the blowing device'is in operation. 1

Referring more particularly to the drawing, 20 designates a. rock drill comprising, as casing parts, a cylinder 2|, front andback heads 22 and 23, respectively, and a front cylinder washer 24 interposed between the cylinder and the front head 22 and extending part way into each to centralize them with respect to eachother.

The cylinder 2! is suitably bored to provide a having afree exhaust port 26 and containing a reciprocatory hammer piston 21 that controls the exhaust port 26. The piston 21 is of the differential type, havinga fluted extension 28 at its front end which extends slidably through the front cylinder washer 24 and is interlockingly engaged, in a well known manner, with a chuck nut 29 threaded into ahollow chuck '30 rotatable in the front head 22.

The interior of the chuck nut 29 and th adjacent portion of the interior of the chuck 30 constitute a cavity 3| into which extends the shank end 32 of a working implement, such as a drill steel, to receive the blows of the hammer piston 21. The drill steel, is suitably guided by a bushing 33 within the chuck 30 and has an opening extending axially therethrough for conveying cleansing medium into the hole being drilled. V V

In the rearward end of the cylinder 2| is an enlarged bore 35 to accommodate a valve mechanism 35 and a rotation mechanism 31, the valve drill ,hole for removing the nismand serves as; aseat for the which may be clamped in assembled position in date a valve 40 that serves to mechanism 36 being armed a the bottm'; r

the bore 35] to form a closure forzth rearward end of the pist'on chamber .25., The rotation w mechanism, in turn, seats upon the valve mechaback head 23 any Well known manner."

'I'hexvalvemechanism 36 is of the," typeshown in United States Patent No. 1,975,229 t0G.'W.

Hulshizer and accordingly comprises awalve chest 38 having a valve chamber-39-to accommosure-fluidto thev ends of the pistonchamber for actuating the piston 21-; Th pressure fluid used for this purposeflows'into the rearward endrof the piston chamber through aninlet passage Al 7 j in the frontend of the valvechest 38,and presinvention and showing the valve and piston elein positions which they may assume during the normal operation of the V passages and 42 alsoserve,

sure fluid is conveyed tofthe front end of the vpiston chamber'byan inlet passage leading from the rearward end of the valve chamber 39 to the front end of thepiston chamber 25. The:inlet resp ctively; t convey actuating fluid to front and rear pressure surfaces and 44, onthe valve40 formov' ing said valve to its limiting positions.

The rotation mechanism 31:1'nay also-be of a well known type comprising a rifle bar 45 that extends through the valve mechanismfand-into the piston 21 wherewith it is slidably interlocked.

The rifle bar carries the usual'rhead 46 having pawls 41" for cooperation withthe teeth ;48 of a ratchet ring 49, encircling the head ,46, to determine the rotative and stationary periods of the rifle bar and therefore, of the piston and' the elements interlockingly connected with, the

piston.

The ratchet; ring 4 9;is held flrmlyi-againstthe valve chest 38 by the back head, and in the lat}- ter is a cavity 50 to accommodate, aplug 5| that serves as an anchor for an end of a water tube 52 to which wateris conveyed by asupply passage 53. The'water' tube extends through the rifle'bar 45 and the piston- 21 and, normally, into the rearward end of the passage, 34 in the work ingimplement. Preferably the'restricted portion 54 of the bore in the piston 21 through whichthe tube 52 extends is -sufliciently larger thangthe tube so thatpressurefluid passing through the flutes in the: rifle bar-'45 into the pistonflmay also flow readily through the restrictedzportion' 54 into the cavity-3| andinto thepassageid in the working implement. p v,

-The, pressure fluid thus passing through, the piston'flows. from th rearward distribute the pres- 7 end of the piston chamber-and its-flow 'must, therefore, be inter.-

from the piston chamber through the passage into the cavity.

4. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a free exhaust port therefor, a reciprocatory piston in the piston chamber to control the exhaust port, a valve for eflecting' the distribution of pres' sure fluid to the piston chamber to actuate the piston and having a pressure surface, a cavity in the casing, a passage leading fr m the exhaust port tothe cavity and being in'constant com-1 v V munication with the piston chamber throughthe exhaust port,. a conduit in the casingQt aIT-ord communication between the pressure surface and the atmospheraand control means forselectively from the piston preventing the exhaust of fluid r chamber through the exhaust port-to the atmosphere and to communicate the conduit with the atmosphere to cause the valve to assume a posi'-. tion for charging one end of the'piston cham-i' ber to hold the piston in position to'uncover the: I i

exhaust port and thereby permit the flow of pressure fluid from the piston chamber through I, i

the passage into thecavity.

WIL IAM A. MORRIS N." 

